8,648 research outputs found

    Focal Plane Alignment and Detector Characterization for the Subaru Prime Focus Spectrograph

    Full text link
    We describe the infrastructure being developed to align and characterize the detectors for the Subaru Measurement of Images and Redshifts (SuMIRe) Prime Focus Spectrograph (PFS). PFS will employ four three-channel spectrographs with an operating wavelength range of 3800 A˚\AA to 12600 A˚\AA. Each spectrograph will be comprised of two visible channels and one near infrared (NIR) channel, where each channel will use a separate Schmidt camera to image the captured spectra onto their respective detectors. In the visible channels, Hamamatsu 2k x 4k CCDs will be mounted in pairs to create a single 4k x 4k detector, while the NIR channel will use a single Teledyne 4k x 4k H4RG HgCdTe device.Comment: 16 pages, 27 figures, SPIE ATI Montreal 201

    Elliptic curves with a given number of points over finite fields

    Full text link
    Given an elliptic curve EE and a positive integer NN, we consider the problem of counting the number of primes pp for which the reduction of EE modulo pp possesses exactly NN points over Fp\mathbb F_p. On average (over a family of elliptic curves), we show bounds that are significantly better than what is trivially obtained by the Hasse bound. Under some additional hypotheses, including a conjecture concerning the short interval distribution of primes in arithmetic progressions, we obtain an asymptotic formula for the average.Comment: A mistake was discovered in the derivation of the product formula for K(N). The included corrigendum corrects this mistake. All page numbers in the corrigendum refer to the journal version of the manuscrip

    The last mile:Using local knowledge to identify barriers to sustainable grain legume production

    Get PDF
    Grain legumes (or pulses–annual leguminous crops that are harvested solely for their dried seeds such as lentils or chickpeas) are essential for sustainable cropping systems. They positively contribute to soil fertility and agricultural biodiversity and are a highly nutritious food source, yet they remain under-exploited across the world. In India–soon to be the world's most populous country and the world's largest importer, producer and consumer of pulses–they are substantially under-utilized and are the only major food group not to have increased in output since independence in 1947. Existing efforts to address low grain legume production have focused on the scientific and agronomic barriers, with little impact on productivity. In contrast, this project, using Tripura in India as a case study, recognizes the limits of imposing top-down solutions and instead focuses on the barriers to production as identified by the growers themselves. Working with 440 farmers from 19 non-tribal and 11 tribal villages in Tripura, NE India, we used facilitated discussion to identify their key barriers to pulse production, and facilitated pile sorting to identify the commonly consumed, grown and available pulses. Twenty-eight barriers to legume production were identified by farmers. The eight principal barriers were: insufficient water; lack of technical knowledge; unreliable seed supply; lack of processing units; soil fertility; financial constraints; limited fertilizer supply; and insufficient fencing material. These barriers are complex and overlapping and originate from system level failures to sufficiently prioritise grain legumes compared to cereals. However, recognizing the length of time it takes to address system level problems, in this paper we identify five immediately applicable mitigating strategies to help overcome the principle barriers identified here. Importantly, these will also create an improved environment to apply the technologically sophisticated grain legume R&D that has been carried out over the last 20 years but has yet to have a measurable impact on pulse production. Therefore understanding the wider socio-economic pathways to sustainable pulse production is essential to facilitate change on the ground. Our results, relevant to policy makers in India and around the world, demonstrate the value of listening to farmers when attempting to improve production, and emphasize the necessity of including the socio-economic systems surrounding pulse production, to complement the current emphasis on biological barriers

    A flight investigation of a terminal area navigation and guidance concept for STOL aircraft

    Get PDF
    A digital avionics system referred to as STOLAND has been test-flown in the NASA CV-340 to obtain performance data for time-controlled guidance in the manual flight director mode. The advanced system components installed in the cockpit included an electronic attitude director indicator and an electronic multifunction display. Navigation guidance and control computations were all performed in the digital computer. Approach paths were flown which included a narrow 180-deg turn and a 1-min, 5-deg straight-in approach to the 30-m altitude go-around point. Results are presented for 20 approaches: (1) blended radio/inertial navigation using TACAN and a microwave scanning beam landing guidance system (MODILS) permitted a smooth transition from area navigation (TACAN) to precision terminal navigation (MODILS), (2) guidance system (flight director) performance measured at an altitude of 30.5 m was within that prescribed for category II CTOL operations on a standard runway, and (3) time of arrival at a point about 2 mi from touchdown was about 4 sec plus or minus sec later than the computed nominal arrival time

    A flight investigation of a terminal area navigation and guidance concept for STOL aircraft

    Get PDF
    A digital avionics system was installed in the CV-340 transport aircraft. Flight tests were made to obtain preliminary performance data in the manual flight director mode using time controlled guidance. These tests provide a basis for selection of terminal area guidance, navigation, and control system concepts for short haul aircraft and for investigating operational procedures

    A Periodically-Forced Mathematical Model for the Seasonal Dynamics of Malaria in Mosquitoes

    Get PDF
    We describe and analyze a periodically-forced difference equation model for malaria in mosquitoes that captures the effects of seasonality and allows the mosquitoes to feed on a heterogeneous population of hosts. We numerically show the existence of a unique globally asymptotically stable periodic orbit and calculate periodic orbits of field-measurable quantities that measure malaria transmission. We integrate this model with an individual-based stochastic simulation model for malaria in humans to compare the effects of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) in reducing malaria transmission, prevalence, and incidence. We show that ITNs are more effective than IRS in reducing transmission and prevalence though IRS would achieve its maximal effects within 2 years while ITNs would need two mass distribution campaigns over several years to do so. Furthermore, the combination of both interventions is more effective than either intervention alone. However, although these interventions reduce transmission and prevalence, they can lead to increased clinical malaria; and all three malaria indicators return to preintervention levels within 3 years after the interventions are withdraw

    A Periodically-Forced Mathematical Model for the Seasonal Dynamics of Malaria in Mosquitoes

    Get PDF
    We describe and analyze a periodically-forced difference equation model for malaria in mosquitoes that captures the effects of seasonality and allows the mosquitoes to feed on a heterogeneous population of hosts. We numerically show the existence of a unique globally asymptotically stable periodic orbit and calculate periodic orbits of field-measurable quantities that measure malaria transmission. We integrate this model with an individual-based stochastic simulation model for malaria in humans to compare the effects of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) in reducing malaria transmission, prevalence, and incidence. We show that ITNs are more effective than IRS in reducing transmission and prevalence though IRS would achieve its maximal effects within 2 years while ITNs would need two mass distribution campaigns over several years to do so. Furthermore, the combination of both interventions is more effective than either intervention alone. However, although these interventions reduce transmission and prevalence, they can lead to increased clinical malaria; and all three malaria indicators return to preintervention levels within 3 years after the interventions are withdrawn

    Symptom relief with moderate dose chemotherapy (mitomycin-C, vinblastine and cisplatin) in advanced non-small cell lung cancer.

    Get PDF
    Twenty-four symptomatic patients with advanced non-small cell lung cancer (NSCLC) were treated with cisplatin-based chemotherapy (mitomycin-C 8 mg m-2 q 6 weeks, vinblastine 6 mg m-2 q 3 weeks, cisplatin 50 mg m-2 q 3 weeks). Patients were assessed for symptom relief as well as for objective response. Although only five patients achieved an objective response (21%), 18 patients (75%) reported a complete disappearance or good improvement in at least one of their tumour-related symptoms. The overall symptomatic response rate was 67% with 16 patients feeling better or much better on treatment. The toxicity of treatment (primarily myelosuppression and nausea and vomiting) was mild and hair loss was minimal. The high incidence of symptomatic relief seen in this study, even in the absence of objective response, suggests that moderate dose chemotherapy may have a role in the palliation of NSCLC
    corecore